CN Andromedae (CN And) is an eclipsing binary star in the constellation Andromeda. Its maximum apparent visual magnitude is 9.62 and drops down to a minimum of 10.2 during the main eclipse. It is classified as a Beta Lyrae variable with a period roughly of 0.4628 days.[3]

CN Andromedae

The visual band light curve of CN Andromedae, adapted from a plot presented by Varol Keskin[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Andromeda
Right ascension 00h 20m 30.54209s[2]
Declination +40° 13′ 33.80342″[2]
Apparent magnitude (V) 9.62 – 10.21 variable [3]
Characteristics
Spectral type F5V[3]
Apparent magnitude (B) 10.24[4]
Apparent magnitude (V) 9.706[4]
Apparent magnitude (G) 9.6637[2]
Apparent magnitude (J) 8.670[5]
Apparent magnitude (H) 8.452[5]
Apparent magnitude (K) 8.427[5]
B−V color index 0.49725[4]
Variable type EB[3]
Astrometry
Radial velocity (Rv)−24.2±1.0[6] km/s
Proper motion (μ) RA: −8.549±0.054 [2] mas/yr
Dec.: −35.291±0.024[2] mas/yr
Parallax (π)4.9670 ± 0.0425 mas[2]
Distance657 ± 6 ly
(201 ± 2 pc)
Orbit[6]
Period (P)0.4627952±0.000035 days
Semi-major axis (a)3.066±0.035
Inclination (i)68.51±0.17°
Periastron epoch (T)HJD 2445231.51710±0.00059
Details
Primary
Mass1.433±0.030[7] M
Radius1.48±0.03[7] R
Luminosity3.40[7] L
Surface gravity (log g)4.24[6] cgs
Temperature6,450[7] K
Secondary
Mass0.552±0.020[7] M
Radius0.95[7] R
Luminosity0.40[7] L
Surface gravity (log g)4.22[6] cgs
Temperature4,726[7] K
Other designations
2MASS J00203054+4013337, BD+39 59, TYC 2787-1815-1
Database references
SIMBADdata

System

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The two stars in this system orbit very close to each other; their spectrum cannot be separated and as a whole they have a spectrum of an F5V star. They are in marginal contact,[7] and there is a mass flow from the primary star to the secondary at a rate of 1.4 × 10−7 M yr−1.[6] The binary orbit is slowly decaying at rate 1.5*10−7 days/year. The third suspected component of the system is the red dwarf star with mass about 0.11 M, at 38±4 years orbit around binary. [8]

Variability

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Confirmation of the variability of CN Andromedae was announced by R. Weber in 1956.[9] The light curve of the star shows a primary eclipse, with its brightness dropping down to 10.21 magnitude, and a secondary one down to a magnitude of 9.9.[3] This phenomenon repeats with a cycle of approximately 11.1 hours, with period decreasing in time due to the mass transfer from one star to the other.[6]

References

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  1. ^ Keskin, Varol (March 1989). "Light Changes of the Close Binary System CN Andromedae". Astrophysics and Space Science. 153 (2): 191–199. Bibcode:1989Ap&SS.153..191K. doi:10.1007/BF00636655. S2CID 117239888. Retrieved 7 October 2021.
  2. ^ a b c d e f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  3. ^ a b c d e CN And, database entry, Combined General Catalog of Variable Stars (GCVS4.2, 2004 Ed.), N. N. Samus, O. V. Durlevich, et al., CDS ID II/250 Accessed on line 2018-10-17.
  4. ^ a b c Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy & Astrophysics, 355: L27–L30, Bibcode:2000A&A...355L..27H.
  5. ^ a b c Cutri, Roc M.; Skrutskie, Michael F.; Van Dyk, Schuyler D.; Beichman, Charles A.; Carpenter, John M.; Chester, Thomas; Cambresy, Laurent; Evans, Tracey E.; Fowler, John W.; Gizis, John E.; Howard, Elizabeth V.; Huchra, John P.; Jarrett, Thomas H.; Kopan, Eugene L.; Kirkpatrick, J. Davy; Light, Robert M.; Marsh, Kenneth A.; McCallon, Howard L.; Schneider, Stephen E.; Stiening, Rae; Sykes, Matthew J.; Weinberg, Martin D.; Wheaton, William A.; Wheelock, Sherry L.; Zacarias, N. (2003). "VizieR Online Data Catalog: 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)". CDS/ADC Collection of Electronic Catalogues. 2246: II/246. Bibcode:2003yCat.2246....0C.
  6. ^ a b c d e f Van Hamme, W.; Samec, R. G.; Gothard, N. W.; Wilson, R. E.; Faulkner, D. R.; Branly, R. M. (2001). "CN Andromedae: A Broken-Contact Binary?". The Astronomical Journal. 122 (6): 3436–3446. Bibcode:2001AJ....122.3436V. doi:10.1086/324110.
  7. ^ a b c d e f g h i Siwak, M.; Zola, S.; Koziel-Wierzbowska, D. (2010). "A Study of Contact Binaries with Large Temperature Differences between Components". Acta Astronomica. 60 (4): 305–336. arXiv:1011.5682. Bibcode:2010AcA....60..305S.
  8. ^ Yildirim, Muhammed (2019). "CN Andromedae: a shallow contact binary with a possible tertiary component". Research in Astronomy and Astrophysics. 19 (1): 10-1–10-10. doi:10.1088/1674-4527/19/1/10.
  9. ^ Weber, R. (January 1956). "Examen de 138 étoiles du "Catalogue of suspected variable stars"". Journal des Observateurs. 39: 113. Bibcode:1956JO.....39..113W. Retrieved 30 October 2024.